The present invention generally relates to mobile surface cleaning machines, particularly to mobile floor surface cleaning machines, and specifically to surface cleaning machines having the ability to dump debris from its hopper at multiple levels above the surface and to surface cleaning machines having a plurality of longitudinally staggered brushes positioned within the longitudinal extent of a one piece, U-shaped squeegee.
Surfaces such as floors are often cleaned by sweeping and by scrubbing, with machines being available to perform both in a single operation. During sweeping, a drum brush is rotated to sweep the surface over which the machine passes throwing debris into a hopper. It can then be appreciated that it becomes necessary to empty the hopper periodically to allow continued collection of debris. Although various hopper dumping mechanisms have been utilized, shortcomings exist such as but not limited to the ability to dump the hopper at various heights according to the particular debris storage utilized and to the complexity of construction and operation of the dumping mechanism. Thus, a need exists for apparatus and methods for dumping hoppers of cleaning machines overcoming the shortcomings of prior mechanisms.
To scrub floors, streets, parking lots and the like, cleaning machines commonly use multiple disc-like scrub brushes rotating in a horizontal plane to loosen dirt and grime from the surface to be cleaned. A water/soap solution is often used to enhance the cleaning action of the scrub brushes. As the machine moves forward a vacuumized squeegee tool follows behind the scrub brushes and suctions the water/soap solution left by the brushes and deposits the solution into a holding tank. The cleaned surface is left dry enough to allow the flow of traffic to continue uninterrupted. Suitable provisions must be provided for picking up the dirty solution when the scrubber is turned or goes around corners. One approach is to extend the squeegee past the combined width of the scrub brushes. However, this approach prevents the machine from scrubbing close to walls, curbs, or similar abutments. Another approach is to utilize generally longitudinally extending, auxiliary wiping blades to channel the dirty solution on the surface into the squeegee. However, this approach significantly increases the component cost for the wiping blades themselves as well as the mechanism for raising and lowering the wiping blades relative to the surface. Further, such wiping blades are especially prone to damage from engaging non-moveable objects such as door stops, ridges, or the like. Thus a need exists for apparatus and methods for picking up the dirty solution overcoming the shortcomings of prior approaches.
Scrubbing machines of this type are generally self-propelled because of their considerable size and weight. The method of propulsion most commonly employed is a single drive wheel located toward the rear of the machine and approximately centered laterally. Two non-driven wheels are typically located toward the front of the machine, one wheel on each side toward the outside edge of the machine. In machines currently commercially available, the drive wheel is located between the scrub brushes and the vacuumized squeegee tool. An obvious disadvantage of this particular arrangement is that the drive wheel must move through the water/soap path left behind the scrub brushes before the solution can be suctioned up by the squeegee tool. The water/soap solution significantly reduces the coefficient of friction between the drive wheel and the surface being cleaned. This can result in loss of traction, swerving, sliding, and loss of control. Thus, a need also exists for apparatus and methods for eliminating the problem of drive wheels moving through the solution path left behind by the scrub brushes.